Monitoramento da qualidade da água e do uso e cobertura da terra na Cachoeira Alta do Tarumã, Manaus/AM

Abstract

A paradox between the abundance and pollution of urban waters is established in the city of Manaus. In this context, the expansion of the Manaus Metropolitan Beltway complex, a stretch of 8.7 km that includes Av. of Tourism/Tarumã Road, compromises the maintenance of water quality in the streams that drain the area, such as the Alta do Tarumã Waterfall. Through this fact, it was asked: How this road expansion threatens the quality of the water and the forest fragment of the Cachoeira Alta do Tarumã. It was considered as a hypothesis that the negative impacts resulting from the action of the State in this area may be irreparable, aggravating the process of environmental degradation and threatening the fauna and flora of the Urban Ecological Corridor, where the waterfall is inserted. The objective of this study was to analyze the water quality and land use and land cover in the area of Cachoeira Alta do Tarumã, in Manaus/AM, in order to understand the interactions between these two aspects and their influences on the local ecosystem. Characterize the vegetation and water quality in the area surrounding the Alta do Tarumã Waterfall through the Rapid Assessment Protocol (PAR) (2022-2023); Evaluate the water quality in the Alta do Tarumã Waterfall, analyzing variables such as electrical conductivity, dissolved oxygen, pH, total dissolved solids, temperature, and turbidity (2022-2023); To know the changes in land use and land cover in the area that covers the duplication of Avenida do Turismo/Estrada do Tarumã using Planet images (2016-2023). The Hypothetical Deductive method and a qualitative-quantitative methodological approach were used. The techniques and procedures included literature and legislation review, field and experimental study – carried out six times, between June 2022 and May 2022, (collection and analysis of water samples and application of the PAR) at three sampling stations (A, B and C), including the Alta do Tarumã Waterfall (station C), and survey of the PlanetScope satellite image database in the period 2016 and 2023, with the elaboration of maps of land use and cover. The land use and land cover maps for the month of August showed the reduction of primary vegetation, which in 2016 occupied 44.65% of the studied area, and which in 2023 occupies 39.45%, the increase in the urbanized area, which in 2023 is 30.46% and the reduction of the water body, which may be related to the historical event of lower water level of the Rio Negro in 2023. The temporal analysis of land use and land cover in the Tarumã-Açu Hydrographic Basin revealed a significant advance in urbanization between 2016 and 2023, resulting in the reduction of primary vegetation and water cover. The duplication of Avenida do Turismo and the works of the Manaus Metropolitan Beltway intensified environmental impacts, such as erosion, sedimentation and changes in water quality. The aerial images captured at the Alta do Tarumã Waterfall and the data obtained with the water samples from stations A, B and C, showed different color patterns of the water bodies, associated with urban influence, sediment deposition and possible eutrophication process, with impacted and altered stretches. These results highlight the need for conservation and sustainable management measures to minimize anthropogenic impacts in the region.